1. Field of the Invention
The present invention relates to a method of transmitting light and electricity using the same optoelectric printed circuit board (PCB) using surface plasmon polaritons (SPP).
2. Description of the Related Art
Generally, in optoelectric printed circuit boards (PCBs), light is transmitted by a multi-mode optical waveguide formed of a dielectric layer formed of glass, silica, polymer, etc., and electricity is transmitted through electrical tracks formed of a metal such as copper. Accordingly, in a conventional optoelectric PCB, an optical waveguide and electrical tracks are formed separately using different materials for each, and thus the process of manufacturing is complicated and the number of processes is great. Also, since a conventional PCB uses multi-mode transmission, enhancement in transmission speed is limited.
Surface plasmon polaritons occur at the interface of materials with a positive dielectric constant and a negative dielectric constant and propagate in the form of quasi-two-dimensional waves along the interface of the materials. For example, surface plasmon polaritons may occur at the interface between a dielectric such as silica, glass, etc. and a metal thin layer formed inside the dielectric. Such surface plasmon polaritons excited by injected light in one portion and proceed and can emit light again in other portions. Thus, such surface plasmon polaritons can be used in an optical waveguide. However, when the optical waveguide is formed of a metal, light is absorbed by free electrons in the metal due to the high energy of light by ultra high frequency, that is, photon energy, and thus the light is weakened within a few micrometers, and this is too a short distance for light to be used for optical propagation.